@LAKHANI Hi, thanks for posting question here. It is sincerely suggested to contact local support for the firmware update on the local official website.

@Spider_43 Hi, thanks for posting question here. Did it work properly before? It is suggested to update Tether app to latest from Apple Store or Google Play. You may also contact local support for...

@Rilla Hi, thanks for posting question here. It is suggested to upgrade to the latest firmware manually according to the official website~

@ISP-Engineer Hi, thanks for posting question here. May I know who is your ISP? As we know, TP-Link products are compatible with most ISPs in your region.

@Midori Hi, thanks for posting question here. Does your SIM card provide IPv6 service? You may refer to the screenshot below and go to the Web UI of the router to change PDP Type as IPv4.

@brandy316 Hi, thanks for posting question here. It is suggested to follow this guide to troubleshoot~